/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: Admin
 * Date: 2022-12-01
 * Time: 17:49
 */
import java.util.*;

public class Demo3 {

    public static void main(String[] args) {
        long[] array = new long[81];

        array[1] = 1;
        array[2] = 1;

        for(int i = 3; i < 81; i++) {
            array[i] = array[i-1] + array[i-2];
        }

        Scanner scan = new Scanner(System.in);
        while(scan.hasNextInt()) {
            int from = scan.nextInt();
            int to = scan.nextInt();

            long count = 0;
            for(int i = from; i <= to; i++) {
                count+=array[i];
            }

            System.out.println(count);
        }
    }
}
